Avoided Critical Behavior in O(n) Systems

TL;DR

This paper explores how infinitesimal long-range frustrating interactions can prevent critical behavior in O(n) systems, leading to abrupt changes in ordering temperature, exemplified by a doped Mott insulator model.

Contribution

It introduces a simple model demonstrating avoided critical behavior due to long-range frustration, applicable to various physical systems.

Findings

Long-range frustration causes discontinuous drops in ordering temperature.

The doped Mott insulator model exhibits avoided criticality.

The model serves as a paradigm for other frustrated systems.

Abstract

Long-range frustrating interactions, even if their strength is infinitesimal, can give rise to a dramatic proliferations of ground or near-ground states. As a consequence, the ordering temperature can exhibit a discontinuous drop as a function of the frustration. A simple model of the doped Mott insulator, where the short-range tendency of the holes to phase separate competes with long-range Coulomb effects, exhibits this "avoided critical" behavior. This model may serve as a paradigm for many other systems.